Cloning, Sequencing, and Detection of MHC-DAB II Gene Polymorphism in Silver Carp (Hypophthalmichthys molitrix)

Continuous monitoring of aquatic genetic diversity among different populations in fish hatcheries is an essential requirement to maintain the viability and sustainability of aquaculture industry. The aim of this study was cloning, sequencing, and detection of major histocompatibility complex (MHC) class II β in silver carp. In this experimental study, the polymorphism of MHC class II β in 138 species of silver carp was studied in 4 different hatcheries of Iran (Guilan, Mazandaran, Golestan, and Khuzestan provinces) in addition to an imported group from China. By polymerase chain reaction (PCR), Hymo-DAB gene amplification was performed and the different haplotypes of the samples were analyzed by single-strand conformation polymorphism (SSCP) method and the sequences obtained with ClustalW2 were matched in Geneious 4.8.5 software and the phylogeny tree of the sequences was plotted. The PCR reaction of the MHC-DAB II genome of the silver carp with a weight of about 350bp without side band was obtained in the samples, indicating the amplification of t Hymo-DAB1*01/DAB2*1 gene in silver carp. The highest and lowest diversity of haplotypes was observed in populations of Khuzestan and Mazandaran. The mean difference between synonymous site (dS) and nonsynonymous site (dN) of alleles was 0.25 and 0.30, respectively, with the ratio of 1.2. The highest allelic richness was observed in samples imported from China (5) and the lowest allelic richness was among Mazandaran species (3.8). Haplotype diversity in silver carp belongs to Hymo-DAB1*01/DAB2*1 gene and among different groups of this species, the highest haplotype diversity is in the Khuzestan population and the highest allelic richness is related to samples imported from China.